/*
 * Copyright (c) 1999, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 */

package java.awt.font;

import java.text.CharacterIterator;

class CharArrayIterator implements CharacterIterator {

  private char[] chars;
  private int pos;
  private int begin;

  CharArrayIterator(char[] chars) {

    reset(chars, 0);
  }

  CharArrayIterator(char[] chars, int begin) {

    reset(chars, begin);
  }

  /**
   * Sets the position to getBeginIndex() and returns the character at that
   * position.
   *
   * @return the first character in the text, or DONE if the text is empty
   * @see getBeginIndex
   */
  public char first() {

    pos = 0;
    return current();
  }

  /**
   * Sets the position to getEndIndex()-1 (getEndIndex() if the text is empty)
   * and returns the character at that position.
   *
   * @return the last character in the text, or DONE if the text is empty
   * @see getEndIndex
   */
  public char last() {

    if (chars.length > 0) {
      pos = chars.length - 1;
    } else {
      pos = 0;
    }
    return current();
  }

  /**
   * Gets the character at the current position (as returned by getIndex()).
   *
   * @return the character at the current position or DONE if the current position is off the end of
   * the text.
   * @see getIndex
   */
  public char current() {

    if (pos >= 0 && pos < chars.length) {
      return chars[pos];
    } else {
      return DONE;
    }
  }

  /**
   * Increments the iterator's index by one and returns the character
   * at the new index.  If the resulting index is greater or equal
   * to getEndIndex(), the current index is reset to getEndIndex() and
   * a value of DONE is returned.
   *
   * @return the character at the new position or DONE if the new position is off the end of the
   * text range.
   */
  public char next() {

    if (pos < chars.length - 1) {
      pos++;
      return chars[pos];
    } else {
      pos = chars.length;
      return DONE;
    }
  }

  /**
   * Decrements the iterator's index by one and returns the character
   * at the new index. If the current index is getBeginIndex(), the index
   * remains at getBeginIndex() and a value of DONE is returned.
   *
   * @return the character at the new position or DONE if the current position is equal to
   * getBeginIndex().
   */
  public char previous() {

    if (pos > 0) {
      pos--;
      return chars[pos];
    } else {
      pos = 0;
      return DONE;
    }
  }

  /**
   * Sets the position to the specified position in the text and returns that
   * character.
   *
   * @param position the position within the text.  Valid values range from getBeginIndex() to
   * getEndIndex().  An IllegalArgumentException is thrown if an invalid value is supplied.
   * @return the character at the specified position or DONE if the specified position is equal to
   * getEndIndex()
   */
  public char setIndex(int position) {

    position -= begin;
    if (position < 0 || position > chars.length) {
      throw new IllegalArgumentException("Invalid index");
    }
    pos = position;
    return current();
  }

  /**
   * Returns the start index of the text.
   *
   * @return the index at which the text begins.
   */
  public int getBeginIndex() {
    return begin;
  }

  /**
   * Returns the end index of the text.  This index is the index of the first
   * character following the end of the text.
   *
   * @return the index after the last character in the text
   */
  public int getEndIndex() {
    return begin + chars.length;
  }

  /**
   * Returns the current index.
   *
   * @return the current index.
   */
  public int getIndex() {
    return begin + pos;
  }

  /**
   * Create a copy of this iterator
   *
   * @return A copy of this
   */
  public Object clone() {
    CharArrayIterator c = new CharArrayIterator(chars, begin);
    c.pos = this.pos;
    return c;
  }

  void reset(char[] chars) {
    reset(chars, 0);
  }

  void reset(char[] chars, int begin) {

    this.chars = chars;
    this.begin = begin;
    pos = 0;
  }
}
